How is the number of cars per train determined for commuter rail

I live close to work, but I often take commuter rail for adventures, which means typically not in rush hour even on weekdays when I’m on vacation. I often find the trains really empty, like sometimes only 5 passengers in a bilevel car that can seat over 100 and once I was the only person in a cab car besides the engineer and conductor (the Rotem cab car has 173 seats). I thought maybe it’s just a Metrolink (LA metro area) thing and LA transit isn’t splendid. In LA, the most occupied Metrolink train I’ve been on was on the San Bernardino line from San Bernardino to LA Union Station on a weekday evening and the car I was in was only about 1/3 occupied. I visited Chicago in the summer and took the Metra a lot for adventures; it was also quite empty off peak so it was probably not just LA. I feel like, isn’t that a huge waste of energy, like the fuel to start and accelerate the train and get it up hill and the AC for all the empty space? How do they determine how many cars to use per train?

OK, maybe it’s empty because it’s off peak, so I looked up some data. For LA Metrolink, the San Bernardino line is the busiest from January to March 2024 (data here: https://metrolinktrains.com/about/agency/facts--numbers/), with on average about 207 passengers per train, but the average is misleading because peak hour trains would be more occupied. So I guess say 400 passengers per train at the very peak time and segment, which makes the typical 4 or 5 car consist of Metrolink reasonable. From a similar calculation, Caltrain’s 5 car consist is also reasonable. Probably Metrolink determines how many cars to use based on the very peak time and segment and adds some more seats due to variability in the number of passengers and to make passengers more comfortable. Is that correct? But why don’t they drop off the extra cars for off peak? More work than turning around and they don’t turn around hence the cab ca

[quote user=“kittysharyo”]
I live close to work, but I often take commuter rail for adventures, which means typically not in rush hour even on weekdays when I’m on vacation. I often find the trains really empty, like sometimes only 5 passengers in a bilevel car that can seat over 100 and once I was the only person in a cab car besides the engineer and conductor (the Rotem cab car has 173 seats). I thought maybe it’s just a Metrolink (LA metro area) thing and LA transit isn’t splendid. In LA, the most occupied Metrolink train I’ve been on was on the San Bernardino line from San Bernardino to LA Union Station on a weekday evening and the car I was in was only about 1/3 occupied. I visited Chicago in the summer and took the Metra a lot for adventures; it was also quite empty off peak so it was probably not just LA. I feel like, isn’t that a huge waste of energy, like the fuel to start and accelerate the train and get it up hill and the AC for all the empty space? How do they determine how many cars to use per train?

OK, maybe it’s empty because it’s off peak, so I looked up some data. For LA Metrolink, the San Bernardino line is the busiest from January to March 2024 (data here: https://metrolinktrains.com/about/agency/facts--numbers/), with on average about 207 passengers per train, but the average is misleading because peak hour trains would be more occupied. So I guess say 400 passengers per train at the very peak time and segment, which makes the typical 4 or 5 car consist of Metrolink reasonable. From a similar calculation, Caltrain’s 5 car consist is also reasonable. Probably Metrolink determines how many cars to use based on the very peak time and segment and adds some more seats due to variability in the number of passengers and to make passengers more comfortable. Is that correct? But why don’t they drop off the extra cars for off peak? More

Balt is right. While train size on Metra is no longer adjusted for lower ridership in the midday (CTA is the same way), not every car is open for service on the midday trains.

Are these ex-IC lines still owned by CN. They require a certain number of axels (32?) per train.

I am surprised that those operating under the CN axle restrictions haven’t taken CN to court to for forcing the secondary users to subject their operations to unsafe signal systems.

The electrified suburban lines, which are mostly separate from the parallel freight and passenger lines, are owned and operated by Metra.

Many commuter services are length-limited first by platform length and then by adjacent grade crossings that are blocked by ‘overhanging’ power or cab cars.

The gains from operating shorter consists during the day are normally far outweighed by the cost of switching cars in and out of consists, particularly when there is a dedicated ‘cab car’ on the far end. Subway and elevated operations with MU equipment can often ‘afford’ to run shorter trains in off-peak service, but there is far less ‘economy’ in doing this for heavy-rail off-peak service (compared to the alternative mentioned, which is to cut off lighting and A/C to some of the cars in an otherwise-fixed consist).